The Chance-Part One
by AgentSmudge
Summary: First part in what could be a trilogy: Sans gets one more chance to bring back what was lost years ago. With his brother and Frisk's help, it's possible they can save the one who build The Core. But when all is finished in the end, can they save themselves? (Rated T for character death, read at own risk (I will put a warning before the chapter))[CURRENTLY ON HIATUS]
1. That Dang Tuesday

So this first chapter is pretty short, but I'm hoping they'll get longer as I go. I already have the next few written and they are longer than this one lol.

I'm not the greatest writer ever, but hey, It's a past time. It's something I enjoy and if I can't draw the scene I'm thinking in my head, I write it out.

That being said, it's not perfect, but enjoy anyway!

(Also I have the entire plot written down, so I won't abandon this story. There's soooo much to write, muahahah!)

* * *

Life on the surface was hard to get used to at first. Humans would either love or loath you if you were a monster. Some monsters couldn't get jobs no matter how hard they looked for one.

The humans just didn't care. In fact, a lot of them wanted the monsters back underground. Even if Asgore had some authority on the surface, it wasn't enough to keep the monsters satisfied. It had been almost a year since they bought homes on the surface. That was the easiest part, considering the monsters had a ton of gold. Mettaton was even able to buy himself a mansion in Hollywood. Gold on the surface was one of the only ways monsters were able to get by.

Sans and Papyrus weren't so lucky at first. Sans had almost no gold because he spent it all at Grillby's a few months before, while Papyrus had just enough to buy a small house on the edge of town. They didn't complain. Their house was in a biome in which they could experience all different kinds of weather. Papyrus could enjoy the sun in the summer or the leaves in the fall and Sans could go stargazing in the spring. Sans even had a job as a scientist and assistant to Alphys. Papyrus worked for a car mechanic and enjoyed fixing up the sports cars and race cars that came through.

Everything had been going pretty well for the two brothers. Up until February, everything was fine.

* * *

(Feb. 2, 2016)

It was Tuesday when it started. Random occurrences of objects found misplaced, warped, or gone entirely. It wasn't a huge deal though. Sans and Papyrus never really payed attention to it, that is until parts from Sans' machine became corrupt and unusable or just plain missing.

"papyrus? pap." Sans ran up the stairs of his lab and unknowingly knocked over a container of liquid nitrogen. The contents would have spilled over the stairs, but it looked as if something caught the container before anything could happen. Sans left his stuff in the basement and went to find Papyrus. The machine he was working on had a simple frame with a panel on the side. Wires spread around it and connected to the outlets in the wall.

"Sans? What's wrong?!" Papyrus dropped the bowl of spaghetti he had been making for dinner and held a sauce-dripping spoon in his hand. Sans stopped mid run and looked sorry. Papyrus looked at his spaghetti and back at Sans with a disappointed look.

"uh, sorry bro." Sans' apology was sincere enough that Papyrus didn't even care.

"I forgive you! For the Great Papyrus always forgives!" He shouted and accidentally whipped sauce all over the wall. Sans giggled and took the spoon from his brother. Clearly it was too dangerous for the Great Papyrus to handle.

"So what is it you wanted, brother?" The taller skeleton turned off the stove and went to get the mop.

"have you been in my lab lately?" Sans cut right to the point.

"Nope. I hate going down there. Everything is too messy…" Hi face scrunched up in disgust as he started to mop the floor.

"huh. okay then." Sans shrugged and walked off, but the missing parts kept coming back to his mind. He wasn't about to slave over making more parts, that's for sure, so he needed to find the culprit of the crime. Sans walked downstairs to find some of the parts on his machine had been tweaked.

"you gotta be kidding me." His eyes went dark for a moment, but he controlled himself. He didn't want to build another machine if he could help it. His last machine was destroyed and that had taken him almost two years to build. He didn't want to repeat the same thing again.

"ugh...why me." He buried his skull in his arms and slumped against the desk. After somewhat composing himself, he glanced over his machine and realized it had actually been fixed to some extent. He wondered if it was fixed enough to be in working condition and, out of curiosity, turned it on. Colours flashed around Sans as the machine came to life. For the first time in a long while, he was genuinely excited.

"holy crap. it's actually working." His poker face turned into a grin and he made sure all the plugs were in the outlets. He didn't want the machine to ever turn off again, just in case. Last time he got it to work, Sans tripped over a cable and fried the machine's circuits.

As he was living in the moment, a small alarm came from the panel of the machine, which made Sans' soul drop. He quickly looked over the screen of the machine and read it over a few times to make sure what he was reading was true.

 **[Redacted]**

"no, no, no, no…" _please._ He tried unplugging the machine so it wouldn't blow a fuse on the internal board, but he was too late. The machine smoked and sparked before it turned off completely. The power in the house went out and Papyrus screamed upstairs. Sans didn't even acknowledge his brother and fell to his knees.

He suddenly remembered the last time he saw the word "redacted" on a machine was when he and Gaster had been working on something. Sans stood up and flipped the power switch back on, his face full of disappointment.

Tuesdays sucked.


	2. Just Act Casual, Right?

AN: So this chapter is a little longer, but not quite as long as I thought it was lol. Guess I have no concept of time OR of quantity, haha.

* * *

Sans couldn't shake the feeling he had ever since his machine got fried. He went over to Frisk's house the next day and brought some papers and a container with him. He hadn't seen the kid in a few months, considering she now lived with her parents. Frisk was only thirteen now after all. There wasn't time to see each other anymore. Everyone had their own lives now.

Sans hesitated knocking on the door, but took a breath and eventually did it. He wasn't too fond of the kid's parents and he knew Frisk wasn't going to answer the door. He knocked twice before the humans opened the door.

"Hello, how can I- Oh, Sans it's you.." Frisk's father's expression took a one-eighty when he saw Sans. This caught the skeleton off guard for a moment. Did the kid's parents really not like him _that_ much? Sans concluded that the answer was yes. They viewed Sans as a bad influence.

"hey...is, umm, frisk home?" _Gosh,_ he hated talking to these people. He shifted in the path outside and realized just how tall adult humans were. Frisk's father stood almost two feet taller than Sans, which was a little intimidating. Sans trademark smile faltered as he tried to keep cool.

"Frisk is home, yes. Let me go see if she's busy." The man finally replied. As the man left, Sans let out a breath he didn't know he was holding. Not long after, Sans could hear footsteps running down the stairs at top speed. He peaked into the house and saw Frisk for a split second before being tackled to the ground.

"hey, kid! how's it going?" He asked, trying to sit back up. Frisk laughed and got off of Sans, allowing him to stand. Sans saw Frisk's smile turn into a frown and he was concerned.

"You promised you'd visit every few weeks! It's been almost three months…" Frisk complained. The skeleton almost completely forgot about that promise. _Man_ , he _hated_ making promises.

"sorry, frisk. i've been really busy in the lab." He tried to explain, but she was stubborn. Perhaps a gift would change her mind.

"i got you a gift from pap." As soon as he said that, the kid's mood lightened up. He reached on the ground for the container he dropped when he was tackled.

"it's 'genuine spaghetti from the great papyrus.' at least, that's what he calls it." He handed the container to Frisk. He was glad that Papyrus made a new batch of spaghetti instead of using the floor spaghetti he dropped last night.

"Wow! I miss Papyrus' cooking. I mean, it wasn't _always_ edible, but sometimes it was really good, y'know?" Frisk was beaming and ran inside to put the spaghetti on the counter. She ran back outside and smiled.

"So what made you decide to visit? You want something. I know you do." _perceptive little kid…_

"actually, i need to ask you a few things." He dropped his serious act and grinned. "may i come inside, milady?" He motioned to the doorway. Frisk smiled and gestured for Sans to go ahead on in.

"After you, my good sir." She played along. Sans smiled as they both ran up the stairs to Frisk's room. _guess some things never change,_ he thought. After she shut the door, Frisk flopped on her bed and Sans took a seat in one of her beanbag chairs.

"So what's up?" She was on her stomach, her elbows supporting her head. Sans sat in the chair, one leg crossed over the other, and arms resting on the side.

"well, i'm gonna cut to the point. have you ever met gaster before?" He questioned. He needed answers soon and he hoped Frisk had some. But her expression changed into a frown.

"I remember hearing about him. I don't think I've ever met him though…"

"i see…"

"May I ask why you're asking _me_ about a mentally insane psycho scientist?" Frisk sat up on the bed. Sans glanced at her for a moment, eye glowing blue for a split second.

"he wasn't mentally insane….or psycho. he just….did some regrettable things." He explained and leaned sideways on the chair.

"Okay, fine. But why do you want to know if I've met him?" She was getting tired of the conversation. She wanted to know the important stuff.

"some things in my lab have been tampered with."

"Could have been Pap." She switched to lying on her back.

"nah. it wasn't him." Sans waved that possibility off. Frisk sighed and jumped off the bed.

"Don't you have security cameras around your lab?" She raised an eyebrow. Sans just looked at her. Why didn't he think of that? It was so obvious! Of course he had security cameras. He had two in his lab and one outside, also connected to the alarm system because it scanned for unauthorized intruders.

"wow, i can't believe that slipped my mind." Sans facepalmed as Frisk laughed at him and opened the door.

They went downstairs and found that plates and silverware were spread across the table in a neat fashion. Frisk's family was one of those proper families that didn't tolerate anything out of place. The table was average size, but was covered in a nice tablecloth and plates made of actual silver. Sans wondered how rich this kid's family was.

"Oh hey! Dinner's set up. Did you wanna stay and eat with us?" Frisk almost begged for him to stay, and he could tell she wanted him to.

"i don't know if that's such a great idea...you know your parents don't like me." He stated, but Frisk just rolled her eyes.

"Don't be such a _baby_ , they're just cautious of monsters." She tried to explain, but she knew that wasn't true.

"kid, i'm pretty sure they hate me." He gave Frisk an ' _are you kidding me?_ ' look. She waved him off and grabbed his hand. She practically grabbed him and shoved him into a chair at the table. He didn't like how this dinner was going on in his head. He frowned at Frisk, who in return had a huge grin on her face.

"fine. i'll stay, but if your parents don't like how i do something _my_ way, then too bad." He put up a tough act and crossed his arms, but on the inside was the most nervous he had ever been. Frisk gave him a thumbs up and sat next to him. Sans sat on one of the ends of the table reserved for guests.

Frisk's mom came out of the kitchen and gasped, almost dropping the basket of spices she carried. She immediately noticed Sans at the end of the table, who just waved.

"sup." His wore his signature grin and leaned back in his chair. Frisk facepalmed. This was going to be a long dinner.

* * *

Sans returned home later that evening and headed straight to his lab. It was late at night and Papyrus had fallen asleep on the couch waiting for his brother to come home. He stopped mid-run and looked back at Papyrus. He had been so busy lately, he forgot that tonight was movie night. His brother even had a bowl of popcorn ready for him on the table next to the couch.

"sigh...sorry pap, next time." He took off to the lab.

Sans switched on the lights and was reminded of his failed machine. It sat on the counter and looked mangled. Everything was a mess and Sans didn't feel like cleaning any of it. He left the pile of parts alone and went over to the computer to check the video footage.

"alright...let's see." He mumbled to himself as he skimmed the tapes. He found one that was triggered after he left his lab a few days ago. It showed a still screen and for a split second Sans thought it was an image, but then a part moved. It's like it was tapped accidently. He checked another video from Tuesday and flinched as he saw himself bump the liquid nitrogen tank next to the stairs. Why didn't he remember picking it back up after he returned? His question was answered as a dark shadowy figure manifested next to the tank and caught it. He couldn't get a good look at the figure's face, but one glance of a cracked, white skull caught his attention.

"gaster."


	3. gaster, did i stutter?

I'm just kinda getting the chapters I've written posted so I don't have to do it later. The story starts to take place during this chapter, heueheuhehue!

* * *

Sans wasn't sure what exactly to do. He knew he could only trust one person with the information he had just received from his video camera earlier. He concluded that it was time to pester Frisk once again.

"frisk! i-" Sans was cut off by a finger on his mouth. He looked down, cross-eyed, and moved the hand away.

"Sans, Sans, Sans….Do you. Know. What. Time. It is?." Frisk emphasized each word with a step towards the skeleton. Sans finally noticed that Frisk was now about an inch taller than him and took a step back.

"look, kid. i know what time it is, but i have to tell you something!" He pleaded. Frisk stood in the doorway, her eyes threatening to close.

"Do you _actually_ know what time it is?"

"...no." Sans concluded, "but that's not the point here."

"Then please, for the love of all things good, tell me what the problem is so I can go to sleep!" She shouted.

"gaster."

"What?" Her shoulders dropped as if she didn't believe him. Sans rolled his eyes and explained.

"gaster. he was the one messing with my stuff in my lab." Frisk stood for a few seconds before turning to shut the door. Sans took notice and put his hands out to stop her. How could Frisk just brush this off? This was important news!

"no, frisk! wait! i'm telling you the truth." He managed to grab the door before it shut and locked eyes with Frisk. She stared him down like a leopard would with its prey.

"So if it is true, what are you going to do about it?" She held the door open just enough so that she could see Sans' face. He visibly cringed and tried to explain his plan.

"well, i wanna go back and save him."

"Heh! You're crazy." She shut the door. All hope drained from Sans' face as he stood in the cold night air. As he was about to walk away though, Frisk opened the door to reveal she had grabbed a coat and put boots on.

"I'm in." She stated.

"whoa, whoa, you can't come with me…"

"And why not? I'm not ten anymore…" Frisk crossed her arms and Sans sighed.

"look, i don't want something to happen to you while we're with gaster. what if you mess up the time continuum?" He lazily explained as if it were plainly obvious that she would cause trouble with the timeline.

"What if _you_ mess up the time continuum? Hmmm?" Frisk was persistent, Sans gave her credit for that, but he couldn't let her come with him. If Gaster was involved, the situation was going to be tricky. Gaster was known to have experimented… on humans. He didn't want Frisk to be involved in this.

"sorry, kid. no means no this time and i ain't joking around either." He gave her a serious look, which made Frisk frown. She nodded understandingly and closed the door. Sans sighed, put his hands in his pockets and walked home.

* * *

Papyrus had been sleeping but woke when he heard the front door shut. Since skeletons didn't need sleep anyway, Papyrus stayed up the rest of the night and started to make spaghetti for breakfast. He figured it would be the best dish for the morning when Sans would return. Of course, spaghetti was _always_ the best dish for breakfast in Papyrus' eyes. How he was even introduced to spaghetti in the first place, no one will ever know.

He looked out the window and saw that a snowstorm was approaching. Papyrus spotted Sans walking up to the house and he waved through the window. Sans waved back and opened the door to go inside. It was warm and smelled like something was burning, but the older brother shrugged it off. It wasn't unusual for something to be burning in the house.

"hey bro, you're up awfully early." Sans hung his coat on the rack next to the door and grabbed his hoodie.

"Well, I woke up and couldn't go back to sleep, so I decided to make some breakfast." He explained while he was stirring the sauce with the noodles. Sans watched him put some salt in the pot and then grimaced when he saw that hot sauce was also being added.

"-And a touch of salsa for flavor!" Papyrus finished and stirred again.

"uh..bro, that's not-" But Sans was cut off by Pap's hand in his face, trying to shove him away. That didn't stop Sans from giggling however.

"SSSSHHHHHHHhhhhhhhh. I'm trying a new recipe, Sans."

"but that's no-"

"Sans, do you know how to cook? No, you don't. So sit down at the table and wait." Sans did as he was told and sat at the dinner table. There were only three chairs and one of them was duct taped together.

"hey pap, i need to tell you something." Sans spoke up after a few minutes of sitting. He wasn't going to tell his brother that he was going to bring Gaster back, so he needed to make up an excuse.

"What is it, brother?"

"i'm gonna hang out with frisk for a few days...is that okay?" He crossed one leg over the other and relaxed in the chair.

"Why of course! Don't worry about me, for The Great Papyrus will be visiting Undyne this week for cooking lessons anyway!" As Papyrus exclaimed, he accidentally splattered the walls with more spaghetti sauce. Sans didn't even care this time and just laughed. Papyrus groaned and set the spoon on the counter.

"aside from…..that," Sans motioned to the spoon, referring to the incident that had occurred. "you do realize it's like, 4 in the morning and not even close to breakfast time, right?" Sans grinned as Pap's face fell in disappointment and confusion.

Soon after "breakfast," Papyrus headed off to bed to get some more sleep. Sans went downstairs to grab supplies and parts for what he had to do. His plan was to head underground, get to the old basement in their house in Snowdin, fix the time machine, and find Gaster. It seemed simple enough, he just had to execute it.

* * *

He arrived at the gateway to the underground, which was guarded by humans. Sans grunted to himself and put on a smile before walking out from the bushes.

"looks like they really bumped up the security here, huh?" As he spoke, guards were already moving to block the entrance. The humans still weren't on perfect terms with the monsters, so they tended to be very cautious of who could enter and exit the gate.

"Sans…" One of the guards started to address him. "It's certainly been a while. I haven't seen you down here since Papyrus needed something from Snowdin. Why the sudden urge to go back?" The guard smirked at Sans, who in return resisted the urge to growl, so he kept silent.

"You know the procedure. For you to get through, I need to know why you're going back." The guard's tone shifted to a commanding one. Sans kept his hands in his pockets and grinned.

"ah, y'know. too many good memories. forgot a picture down there that i'd like to get back." Although it wasn't entirely a lie, the guard knew that wasn't Sans' true intention.

"Sans, tell me why you're going back or I can't let you proceed." He glared at the skeleton and a few guards looked ready to close in just in case Sans tried something.

"why don't you give the others this much trouble…?" He sighed.

"Because I know your reputation. You can't deceive me anymore." The guard's hand was on his gun by his side. Sans glanced down and realized that he didn't want to get into trouble right now.

"alright, fine. i'm coming back down because i left some schematics in my lab that i can't recreate." Sans was glad that the guard still couldn't figure out when he was lying and when he was telling the truth. After some thought, the guard sighed and shook his head.

"Fair enough. But remember that we have information on you and if you're not back in a week, we'll have to come find you ourselves."

"yeah, yeah, you'll file me as wanted, yadda, yadda." He waved him off as he walked through the gate that was opening. "see ya later, lieutenant."

"I'm a general!"

"whatever." As soon as Sans entered the other side of the gate, he teleported away. The guards saw a gust of wind kick up some snow where Sans had stood just seconds before.


	4. Dweller Beneath the Surface

Well, this chapter is very short...buh. Oh well, I guess enjoy it anyway lol.

* * *

Sans stood outside in the cold blizzard staring at his house. It had been months since he and Papyrus had left it. He grabbed his key and opened the front door. The lights were off and the house had an eerie feel to it. Sans turned the lights on in the hallways and walked up the stairs. He opened the door to his room and saw that everything was where he had left it, minus some papers he took to the surface with him.

He inspected Papyrus' room next and momentarily forgot that his brother had taken much more to the surface than he did. Pap's race car bed was gone, his flag, and action figures had all been packed and ready to move. His room seemed so empty and lifeless now.

Sans closed the door behind him and went to his first lab downstairs. The door outside was hard to open because of the wind blowing against it, so Sans had to force it open with some of his magic. Making his way down the stairs, he realized how small this lab was compared to his new one on the surface. He flipped the light switch and after a few flickers, the lab was visible.

"well, time to get started i suppose…" He grabbed some tools from his backpack he brought and placed them on the counter.

A lot of monsters had actually stayed underground because they still feared what the humans might do. Although the humans decided not to fight the monsters again, the monsters were treated as outcasts and some were even being sold as slaves on the black market. Thankfully, none of Sans' friends had been treated that as bad as that, but they were all still very cautious. Grillby was just as cautious, which was why he decided to stay and work his job at the restaurant.

After a few hours of working on the time machine, Sans needed a break. He decided that fresh air wouldn't be a bad idea and he could stop by Alphys' lab. He knew she had left most of her tools underground and he figured he could use a few.

He walked out the side door to the house and flipped his hood over his skull. The blizzard wasn't letting up, which mean that on the surface (he looks calm and ready to drop spaghetti, but he keeps on forgetti) the humans must have been experiencing a storm of their own. The wind in the underground came from holes in the ceiling that were scattered around. Some were big enough to climb through, but all the holes were far too high for anyone to reach.

After walking through Waterfall to Hotland, Sans realized that the monsters seemed like they were hiding from him. He was curious, but not curious enough to find out what the reason for their behaviour was for. The only thing on his mind was finishing the machine to get Gaster back.

He made a quick trip to Alphys' lab, then returned home. He realized all the lights were off in his lab downstairs and the door had been left open. He didn't remember doing such and scanned the lab for any missing parts. Perhaps Gaster had paid him another visit?

"gaster...must you make things difficult?" Sans spoke aloud to the phantom, almost hoping for a response. He knew it was far fetched to hope for his friend to reply, but he held on to the possibility that maybe he could. Sans sat at his desk and fiddled with the machine some more.

A few hours had passed and Sans had gotten the machine to emit lights when turned on. It was a sign that the time machine was almost ready to be tested out. Sans knew that, as a scientist, he should be testing all of his experiments, but how was he going to test a time machine? He couldn't. His plan was to use it on himself and see what the outcome would be.

When the machine was complete, Sans made sure he had everything he needed before he left. He set the specific time he needed to go back to and entered other various numbers on the keypad. The time machine used determination to bring a monster's soul to another time. Sans was aware of the fact, but didn't worry because he himself possessed enough determination to get home afterwards.

"looks like this is the big moment." He flipped the switch to fully activate the last part of the time machine. A portal about half the height of the room opened before Sans and glowed an eerie red colour. Hesitating to go in, Sans took a step back and put his hand up to shield himself from the bright light. He grabbed his backpack and put on his slippers. Before he entered, he heard a noise behind him and whipped his head to look. He shrugged off the ordeal and stepped through the portal. It was too late to turn back now.

* * *

(Feb. 8, 2009)

A red portal opened above a snowbank on the edge of town. The red had cast a glow that could be seen from miles away. Suddenly, Sans was launched out of the portal and into the snow below him.

"well...that was _just_ great." He remarked, brushing off the powdery snow in the process. He lifted his head and recognized that he was on the edge of Snowdin, outside his house. He was about to open the door when he realized something.

"oh man, i can't let myself see myself…" He had forgotten that this was the past and that there was a possibility that he could run into his past self. He didn't want to corrupt the time continuum.

He looked back at where the portal was and saw that the red glow was still vibrant. Sans turned around and headed to where he knew he could find Gaster: The Royal Scientist's lab.


End file.
